The present technology relates to a planarizing method suitable for a substrate including a resin material, and to a method of manufacturing a driving substrate using the planarizing method. In addition thereto, the present technology relates to a driving substrate and to a display device.
In recent years, a technology has been studied in which, as a substrate which does not crack easily and has flexibility, a film including a resin material (resin film) is used to form a driving substrate of a display device and the like. However, such a resin film has micro concavities and convexities on the surface thereof. Therefore, disconnection and short circuit occasionally occur at a wiring line of a driving circuit provided on the resin film.
For this reason, it is necessary to carry out a step of planarizing a resin film before forming a wiring line and a thin film transistor that configure a driving circuit. Although some methods of planarizing by etching and polishing have been provided (for example, Japanese Unexamined Patent Application Publication Nos. H06-77182, H06-85059, H09-8007, 2002-252195, 2004-50711, 2004-58415, and 2005-30798), it is difficult to put such methods into practical use because of cost issue posed by long production time, small process area, and the like.
In view of this, Japanese Unexamined Patent Application Publication No. 2005-30798 proposes, for practical use, a method in which a protective layer having high etching resistance is provided on a surface of a resin film, and only a convex portion of the resin film protruding from the protective layer is removed by etching.